ABSTRACT
Cities may well be the engines of modern economies, central to the delivery of services that permit ongoing increases in gross domestic product. A finer measure of air quality for cities is the number of days on which ozone levels exceed recommended levels. The Asian Development Bank released an assessment of the state of the environment in Asia. It points to dismal progress and increasing threats to human health in Asia's cities. Emissions of air pollutants lead to the production of smogs that destroy sensitive tissues, the formation of inhalable carcinogenic particles, reduced lung function, and are responsible for many untimely deaths each year. Pollution degrades building materials such as rubbers and stonework, and reduces the visual amenity of scenic vistas. Some urban pollution levels have decreased in many cities, probably due to better emissions management. Two of the key contributors to greenhouse gas emission by cities are demands on transport and electricity.
